Repeat until he will sit for just the hand signal and verbal cue without the lure. If your dog does not sit, bring your arm down and lure him up with the treat in your hand. A second after your arm straightens, say your verbal “Sit” cue. Bring your left arm up in a circular motion in front of your chest with your elbow bent, then straighten it out to your left side, parallel to the ground, in a “ta-da!” sort of flourish. With your dog lying down in front of you, stand with both arms relaxed at your sides.
When he has done at least a half dozen downs without the lure, give the hand signal (arm raised) without the verbal cue. Repeat this exercise until he will lie down for the hand signal and verbal cue without the lure. If your dog does not lie down, lower your right hand to his nose and lure him down with the treat. A second after your arm reaches its full height, fingers pointed toward the ceiling, say your verbal “Down” cue. With your dog sitting in front of you, stand with both arms relaxed at your sides. Down: Hold a treat in your right hand.
No one wants to risk having their dog miss the signal from across the ring! I encourage my students to start with big hand signals, like the ones most people use in obedience competition. Here is how I initially teach hand signals for Down, Sit, and Come.